Folie à deux - French for "a madness shared by two", shared psychosis, or "the theatric of two"

This syndrome is most commonly diagnosed when the two or more individuals concerned live in proximity and may be socially or physically isolated and have little interaction with other people.

Folie imposée is where a dominant person (known as the 'primary', 'inducer' or 'principal') initially forms a delusional belief during a psychotic episode and imposes it on another person or persons (known as the 'secondary', 'acceptor' or 'associate') with the assumption that the secondary person might not have become deluded if left to his or her own devices

UBF chapters created the perfect environment for this to happen. On top of this, my shepard used to have paranoid dilutions about the chapter director and the other members, of which he tried to convince me. Our 1:1's turned more into conditioning sessions to turn me into a more adherent disciple of his, not of Jesus.

One would think that a large group would be the ideal medium for malignant indoctrination, but it turns out that a "one-to-one" relationship can be just as effective. Examples I would give are the Tsarnaev brothers and John Muhammad-Lee Malvo.